A pencil, such as a conventional No. 2 pencil, a cosmetic pencil, or any other type of marking instrument is typically recognized by those of skill in the art as having an outer layer of material commonly constructed from wax, wood, or any other suitable material. An inner core is surrounded by the outer layer and is commonly constructed from graphite, cosmetic lead, or any other suitable marking material. A common problem with pencil sharpening is the removal of the outer layer material with regard to the softer inner core material and the creation of an acceptable tip on the inner core material relative to the outer layer for proper use of the pencil.
One conventional pencil sharpener is a simple plastic device having a receptacle and a metal blade disposed such that a pencil disposed within the receptacle contacts the blade. This pencil sharpener, while very small and portable, has a single blade for sharpening pencils having various different diameters. Another problem is that the shavings from the outer layer must be collected or the pencil must be sharpened over a trash receptacle.
A common solution which overcomes the problem associated with pencil shavings includes a catching retainer, such as a plastic casing, operatively connected to the sharpener in communication with a track from which the shavings emerge, as the pencil is being sharpened. The disadvantage of a single common blade for all pencil diameters remains.
Another conventional pencil sharpener uses an electrical source, such as a battery, for powering an electrical motor which rotates the sharpening blade relative to the pencil. For example, U.S. Pat. No. 6,065,514 describes a compact, hand-held battery-operated cosmetic pencil sharpener. This pencil sharpener includes a blade assembly having two elements each disposed at different angles for sharpening the outer casing of the pencil and the inner wax-like core of a cosmetic pencil. U.S. Pat. No. 6,065,514 also discloses a completely inclusive electrical system, where an electrical source, such as a battery, powers a motor for rotating of the dual element blade. Although U.S. Pat. No. 6,065,514 overcomes disadvantages related to the different materials and orientation of the inner core material and the outer casing material with respect to the process of sharpening a pencil, this prior art reference fails to overcome disadvantages related to pencils with various different diameters.
Therefore, there exists a need in the art for an improved pencil sharpener having, among other benefits, interchangeable heads for providing improved sharpening for pencils of various different diameters.